This invention relates to a cryogenic envelope for a transmission line. In this respect, a preferred embodiment of the invention will be described in connection with a cryogenic envelope for a flexible superconducting power transmission line.
In order to be commercially attractive, superconductive power transmission lines must have low thermal losses and high reliability. Consequently, it is an object of this invention to provide a transmission line having a cryogenic envelope that is both reliable and results in a low-heat-leak structure.
One problem with existing superconductive transmission lines is that the cable container itself is supported within an insulative envelope; and the supporting structures give rise to considerable heat-leak to the superconductive cable. Hence, the preferred embodiment about to be described includes support spacers which have a relatively low tendency to transmit heat to the superconductive cable from the surroundings of the insulative envelope.